garretson



Patented May 17, 1927.

UNITED 1 srarss 1,529,335; PATENT OFFICE.

Imam? n, eannn'rson, or nsw roan; n. in, Assren'on To HARRY WAITE, or roan, n. 1';

er-RAY sys'rniu.

Application filed Ilecembcr 20, 1921. Serial Hop-523,613.

The object of my invention isto provide current measuring and regulating devices so i that the measuring and the regulating will take place entirely at the switclrboard of the system in which my invention is employed and it is particularly applicable to systems where voltages 01 two hundred thousand,

more or less are employed which have two step-up transformers and two rectifying switches which are syncl'ironously driven from common shaft. I (:omplished by my invention, one embodn mentof which is hereinafter more partic-* ularly set forth.

For a more detailed description of my in vention, reference is to he had to the ac- 1 and 2 represent the lead in wires which bring in any suitable current To siu'iplify the illustration and explanatiom it is assumcd that an alternating current goes in over these wires of the usual conunercial kind, and that these wires run to a synchronous motor 3 of any suitable kind and include in the circuit any suitable regulator 1 and switches or other devices, not shown, which may be desirable for use in this connection. The wires 1 and 2 also have wires 5 and 6 connected to them which run to the step-up transformers 7 and 8 respectively. These transformers are made suitable for X-ray work and have their primaries 9 and 10 and their secondaries 11. and 12.

The tube 13 of this system is preferably a large and powerful tube of the hot cathode type. This tube has its anode connected to a wire 14 which runs to one terminal of one rectifying: switch 15 on a shaft 16 which is connected to the armature of the motor 3 and is driven directly by it. The cathode has two wires 17 and 18, one of which, say the wire 18, connected to a wire 19 that runs to a terminal of the rectifying switch 20 which is also mounted on the shaft 16 and is driven by the motor 8. The wire 18 is also connected to one terminal of the secondary 21 of the step-down transformer 22 and the other terminal of this secondary 21 is connected to the wire 17. The primary 23 of this transformer 22 is connected to two wiresflt and 25, the wire 24 being con nected directly to the wire 2 and the wire 25 running to a regulator 26 which includes a This oliiject ac res' tance 27 and a wire 28 connects this armature 29 may rest on a contact 31 when not SLIlJjQCt to the influences of the magnet with suflicient power to draw it away irom this contact. \Vhen this armature rcits on this contact a circuitis established throughthe same to the wire 28, as indi cated. sothat 111 this event the resistance is short circuited. The magnet 30 has one of its ends connected'to a wire 92 which runs to a wire 33 which has one end grounded at 34 andits other end connected to a n'iillian'uneter the other terminal ofthis milliammeter is connected by wire 36 to a terminal of the I rot-titrinn switch 15. The other terminal of the marri'ietfid is connected by anwire 37 to a terminal of the high potential switch 20.: l

The transformers 7 and 8 have their secondaries11 and 12 connected to the/two rectifyii'nr switches 20 and15 by-wires 38, 40 and 411, as shown.

irsstuning that the parts are as indicated, the operation of my improved system is as follows: It being assumed that power is derived through the wires 1 and 2 and that the shaft 16 is rotating so that the high potential switches 15 and 20 are functioning properly. the tube 13 is charged with a cathode heating current through the wires .17 and 18 and at the same timethis tube is charged with an X-ray generating current which on the positivc side comes from the rectifying switch 15 and on the negative side comes fron'i the rectifying switch 20. T racing the current from the cathode t0 the anode through the wire 18 to the wire 19 thence through the rectifying switch 20 to the wire 39, thence through the secondary 11 to the wire 38, thence through the rectifying switch 20 to the wire 37, thence through the relay magnet 30 to the wire 32 and from there through the milliammetcr 35 to the wire 36 and thence through the rectifying switch 15 to the wire 40 and from there through the secondary 12 to the wire 41 and thencethrough the rectifying switch 15 to the wire 14:. When polarity is reversed the circuit is the same except that the current passes -from the wire 19 through the switch 20 to the wire 38 and corresponding changes are made elsewhere so that in any event a "the magnet and then the resistance 27 comes into the circuit of theprimary 23 of the transformer wherchyglhe cathode heating current reduced and the current passing through .hc magnet 30 is correspondinrrlyreduced so that by means of the regulator 26 it is possible for the operator to keep the inilliammeter reading, very nearly constant. 'As he is always reading di rectly from-the current passing through the tube hlS reading is exceedingly accurate,

Furthermore, as the potential of themilliammeter issubstantially groundpotential the operator is in no danger whatsoeverand may observe the instrument to the best ad vantage; This is not possible as such instruments have been observed heretofore because they have'been charged at the high potential of the tube and are tl'iereforc necessarily remote from the person regulatingthe system so that he cannotaccurately read theinstrument. By my improved system accurate and perfect reading at all times and correspond ng regulation is made possible; 1

if this current passing throngl'r \Vhile I have shown and described one embodiment of my invention, it is obvious that it is not restricted thereto, but that it is broad enough to cover all claims that come within the scope of the annexed claim.

Having thus described my invention, what 1 claim is:

In a system of the class described, a milliammeter, a regulating device for regulating the flow of current through a hot cathode of an Xray tube, an X-ray tube of the hot cathode type, means for connecting the hot cathode with a rectifying switch and means for connecting the rectifying witch, with a step-up transformer. means for connecting the anode of the tube with a second rectifying switch and means for connecting the second rectifying switch with a second step'up transformer, means for energizing both transformers, means for driving both rectifying switches synchronously with each other and with the current parting through the step-up transformers, two wires running from two terminals of the rectifying switches, said wires being connected to the said milliammeter and the said regulating, device, a step-down transformer for supplying a cathode heating current to the cathode of the X-ray tube and means for connecting the primary of the step-down transformer with the regulating device, whereby the power of the tube may be regulated.

In testimony whereof, I have hereunto set my hand and seal this 15th day of December,

HARRY D. GARRETSON. 

